1. Technical Field
The present disclosure generally relates to wellbore servicing. More specifically, this disclosure relates to the use of composite compositions to reduce lost circulation.
2. Background
A natural resource such as oil or gas residing in a subterranean formation can be recovered by drilling a well into the formation. The subterranean formation is usually isolated from other formations using a technique known as well cementing. Subsequently, oil or gas residing in the subterranean formation may be recovered by driving the fluid into the well using, for example, a pressure gradient that exists between the formation and the wellbore, the force of gravity, displacement of the fluid using a pump or the force of another fluid injected into the well or an adjacent well. The production of the fluid in the formation may be increased by hydraulically fracturing the formation. That is, a viscous fracturing fluid may pumped down the casing to the formation at a rate and a pressure sufficient to form fractures that extend into the formation, providing additional pathways through which the oil or gas can flow to the well. Unfortunately, water rather than oil or gas may eventually be produced by the formation through the fractures therein. To provide for the production of more oil or gas, a fracturing fluid may again be pumped into the formation to form additional fractures therein. However, the previously used fractures first must be plugged to prevent the loss of the fracturing fluid into the formation via those fractures.
In addition to the fracturing fluid, other fluids used in servicing a wellbore may also be lost to the subterranean formation while circulating the fluids in the wellbore. In particular, the fluids may enter the subterranean formation via depleted zones, zones of relatively low pressure, lost circulation zones having naturally occurring fractures, weak zones having fracture gradients exceeded by the hydrostatic pressure of the drilling fluid, and so forth. As a result, the service provided by such fluid is more difficult to achieve. For example, a drilling fluid may be lost to the formation, resulting in the circulation of the fluid in the wellbore being too low to allow for further drilling of the wellbore. Also, a secondary cement/sealant composition may be lost to the formation as it is being placed in the wellbore, thereby rendering the secondary operation ineffective in maintaining isolation of the formation.
Conventional methods of treating lost circulation take into consideration many aspects related to the type of wellbore servicing operation being carried out. One challenge that may be encountered in the utilization of lost circulation treatments is the use of water-wet or hydrophilic materials to treat formations that are oil-wet. For example, a lost circulation zone may be encountered when drilling with an oil-based mud (OBM). In such instances, the OBM has rendered the formation or environment (e.g., wellbore) oil-wet where the formation or environment contains materials that are oleaginous in nature (e.g., surface of the formation or environment has oleaginous-type residual material). In such instances the use of conventional methods of treating lost circulation (e.g., cement plugs) are less effective due to the ability of the oil-wet material to retard setting of the cement and due to the poor bonding that typically results between the water-based cement and oil-wet formation. These challenges are often addressed by the time-consuming and costly conversion of the oil-wet formation or environment to a water-wet formation or environment before introduction of the cement plug.
Accordingly, an ongoing need exists for compositions and methods of treating lost circulation. Additionally an ongoing need exists for compositions and methods of treating lost circulation in oil-wet formations or environments.